Bandgap references are widely used for Complementary Metal-Oxide-Semiconductor Transistor (CMOS) on-chip regulators. Bandgap references use the parasitic bi-polar transistors on CMOS process to generate the voltage related to bandgap of silicon. However, bandgap references cannot compensate for the Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) variation in process corner and temperature. The process corner refers to the variation of parameter in process. MOSFETs of different chips may exhibit different speed variation within a certain range. When a regulator is used to provide power supply to a digital circuit, the delay time of CMOS gates with different corner conditions will vary dramatically, which makes it harder to achieve the timing convergency for the digital circuit.
With the higher and higher speed achieved on an IC with nano-meter process, the margins for timing tolerance are getting smaller and smaller. It is desirable to design a new regulator with a reference voltage that can compensate for the variation in process corner and temperature of the CMOS.